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Description

This error indicates that a string value being processed by MariaDB (e.g., in a query result, insert, or update) exceeds the maximum allowed size configured by the `max_allowed_packet` system variable. It typically occurs when dealing with large data blobs, long text fields, or complex queries returning extensive output that surpasses the configured limit.

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Error Message

Result string is longer than 'max_allowed_packet' bytes

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Known Causes

4 known causes

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Retrieving Large Data

Attempting to select or retrieve a very long string, BLOB, or TEXT field from the database that surpasses the current `max_allowed_packet` limit on the server.

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Inserting or Updating Big Strings

Trying to insert or update a row with a string value (e.g., a long text document, image data) whose size exceeds the configured `max_allowed_packet`.

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Complex Query Output

The combined length of strings returned by a complex query, such as those involving `GROUP_CONCAT` or multiple concatenated fields, exceeds the `max_allowed_packet` size.

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Client-Side Packet Limit

The client application connecting to MariaDB has its own `max_allowed_packet` setting which is lower than the server's, causing the error even if the server could handle the data.

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Solutions

3 solutions available

1. Temporarily Increase max_allowed_packet for the Current Session easy

Quickly increase the limit for the current connection without server-wide changes.

1

Connect to your MariaDB server using a client (e.g., `mysql` command-line client, DBeaver, phpMyAdmin).

2

Execute the following SQL command to set `max_allowed_packet` to a larger value (e.g., 64MB). Adjust the value as needed based on the size of the data you are trying to process.

SET GLOBAL max_allowed_packet = 67108864; -- 64MB in bytes

3

Now, attempt to execute the query or operation that was previously failing. This setting will only last for your current session.

2. Permanently Increase max_allowed_packet in MariaDB Configuration medium

Modify the MariaDB configuration file to permanently increase the limit for all connections.

1

Locate your MariaDB configuration file. Common locations include `/etc/my.cnf`, `/etc/mysql/my.cnf`, or files within `/etc/mysql/conf.d/` and `/etc/mysql/mariadb.conf.d/`.

2

Open the configuration file with a text editor (e.g., `nano`, `vim`) with root privileges.

sudo nano /etc/my.cnf

3

Find the `[mysqld]` section. If it doesn't exist, create it. Add or modify the `max_allowed_packet` directive to a suitable value (e.g., 64MB). Ensure the value is in bytes.

[mysqld]
max_allowed_packet = 67108864

4

Save the changes and exit the editor.

5

Restart the MariaDB service for the changes to take effect.

sudo systemctl restart mariadb

3. Optimize Queries to Reduce Result String Size medium

Refactor your SQL queries to return only necessary data, avoiding large result sets.

1

Analyze the query that is causing the error. Identify if you are selecting more columns or rows than are strictly needed for the operation.

2

If possible, use `SELECT specific_columns` instead of `SELECT *` to fetch only the required data.

SELECT column1, column2 FROM your_table WHERE ...

3

Consider using `LIMIT` clauses if you only need a subset of the results.

SELECT column1 FROM your_table WHERE ... LIMIT 100;

4

If the operation involves large text or blob data, explore ways to process it in smaller chunks or store it differently if feasible.

5

Re-test your query after optimization.

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Related Errors

5 related errors

MariaDB Error 1162: Result String Too Long